1. Field of the Invention
The present invention relates to a resin composition, and a film obtained therefrom. In particular, the invention relates to a resin composition suitable for a film which has good transparency and heat sealing property and also excellent flexibility and tear resistance, and a film obtained therefrom. The film of the invention can be suitably used as a film for packaging.
2. Description of the Related Art
A stretch film that is used in domestic use or business use for preservation of food or the like is prepared from polyvinyl chloride or polyvinylidene chloride. However, films made of these polymers contain a large quantity of chlorine atoms in the raw material resin, and therefore they have potential for causing generation of dioxin, depending on the methods of disposal and incineration. Thus, development of a composition for wrapping film which does not contain a chlorine atom is in progress.
As the polyolefin-based stretch film which does not contain the chlorine atom, conventionally there are known monolayer or multilayer films having a film made from a composition comprising low density polyethylene and various resins as at least one layer, and monolayer or multilayer films having a film made from a composition comprising polypropylene and various resins as at least one layer. The film made of low density polyethylene is inferior in transparency, whereas the film made of polypropylene has good transparency and strong stiffness, while having a problem of low impact strength.
It is described in JP-A No. 11-228758 that a stretch film with excellent transparency is obtained from a resin composition comprising an ethylene/α-olefin copolymer obtained by using a metallocene catalyst, and low density polyethylene obtained by high pressure radical polymerization. However, when the resin composition according to the publication is formed into a film by, for example, inflation molding, etc., the film has poor transparency and poor heat sealing property and tear resistance, thus imposing limitation in the materials to be packaged (See JP-A No. 11-2287588).
In addition, JP-A Nos. 3-66737 and 9-137013 describe strippable protective films obtained from a composition comprising an ethylene/α-olefin copolymer, a propylene/butene-1 copolymer, and optionally a tackifier. The film obtained from a composition as described in JP-A No. 3-66737 or JP-A No. 9-137013 has excellent tackiness and can be effectively used as, for example, a strippable protective film intended to protect a substrate by being adhered thereto. However, the above-mentioned film may have poor tear strength and impact strength, and thus it can be said only with difficulty that this film is necessarily suitable for the use as packaging film as used in packaging, transporting and storing a content material, as it is the case for a stretch film for example. Further, JP-A No. 3-66737 does not describe on transparency of the film. In JP-A No. 9-137013, although there is mention on transparency, a composition which is well balanced between transparency and tear strength is not described.